Grinding machine-truing apparatus



Aug. 25, 1959 o. E. HlLI- 2,900,974

A GRINDING MACHINE-TRUING APPARATUS Filed March 28, 1958 4 Sheets-Sheet l Fig.2 90

INVENTOR O VA E2 HILL Muse! JHLCQRNE Aug. 25, 1959 o. E. HILL 2,900,974

GRINDING MACHINE-TRUING APPARATUS Filed March 28, 1958 4 Sheets-Sheet 2 v INVENTOR Fig. 3 O/VA E. H/u.

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Aug. 25, 1959 Q E, HILL 2,900,974"

GRINDING MACHINE-TRUING APPARATUS Filed March 28, 1958 4 Sheets-Sheet 3 moi;

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ATT. QFIMEY Aug; 25, 1959 Filed March 28, 1958 o. E. HILL GRINDING MACHINE-TRUING APPARATUS 4 Sheets-Sheet 4 INVENT'OR 'O/vA E. HILL" was AI oE/va/ United States Patent O GRINDING MACHINE-TRUING APPARATUS Oiva E. Hill, West Boylston, Mass, assignor to Norton (ifmpany, Worcester, Mass, a corporation of Massac usetts Application March 28, 1958, Serial No. 724,671

Claims. (Cl. 125--'11) The invention relates to grinding machines, and more particularly to a grinding wheel truing apparatus.

One object of the invention is to provide a simple and thoroughly practical grinding wheel truing apparatus for truing a predetermined shape or form on the operative face of a grinding wheel. A further object of the invention is to provide a truing apparatus having a longitudinally movable slide which supports an angularly arranged truing tool slide which is arranged so that the resultant thrust of a follower on the forming bar serves to impart a transverse movement to the truing tool so as to facilitate truing vertical or other irregular shapes on the operative face of a grinding wheel. Another object is to provide a longitudinally adjustable forming bar which serves to facilitate adjusting the path of movement of the truing tool in setting up the apparatus, or to facilitate compensation for truing tool wear.

A further object of the invention is to provide a longitudinally movable slide having predetermined or angularly diverging transversely movable slides each of which supports a truing tool combined with independent follower and forming bars for controlling the path of movement of each of the truing tools as to true overlapping paths on the periphery of a grinding wheel. A further object is to provide such an arrangement to facilitate truing opposite side faces or shapes both external and internal on the peripheral face of the grinding wheel.

Another object is to provide independent longitudinally adjustable forming bars for controlling the paths of movement of each of the truing tools to facilitate varying the path of one truing tool relative to the other, and also to facilitate compensation for truing tool wear. Other objects will be in part obvious or in part pointed out hereinafter.

In the accompanying drawings in which is: shown one of various possible embodiments of the mechanical features of this invention;

Fig. 1 is a front elevation of the improved grinding wheel truing apparatus;

Fig. 2 is a plan view of the truing apparatus;

Fig. 3 is a vertical sectional view, on an enlarged scale, taken approximately on the line 3-3 of Fig. 1;

Fig. 4 is a front elevation of a modified form of the tuning apparatus in which two truing tools are provided for truing complex external shapes on the operative face of the grinding wheel;

Fig. 5 is a similar front elevation of a modified form of the truing apparatus in which two truing tools are provided for truing complex reentrant or internal shapes on the operative face of a grinding wheel;

Fig. 6 is a fragmentary vertical sectional view, taken approximately on the line 6-6 of Figs. 4 and 5, through the duplex forming bar;

Fig. 7 is a fragmentary plan view, showing the connection between the truing tool feeding mechanisms; and

Fig. 8 is a combined electric and hydraulic diagram of the actuating mechanisms and the controls therefor.

A grinding wheel truing apparatus has been illustrated U 2,900,974 Patented Aug. 25, 1959 in the drawings. A grinding wheel 10 to be trued is partially surrounded by a wheel guard 11. The wheel guard 11 serves as a support for a housing 12 which supports the truing apparatus. The truing apparatus is similar to that disclosed in my prior United States patent application Serial #626,484 filed December 5, 1956. The truing apparatus is provided with a longitudinally movable slide 13 which is arranged to slide longitudinally, that is in the direction substantially parallel to the axis of the grinding wheel 10. An anti-friction slideway is provided for the slide 13 comprising a member 14 which is fastened to the housing 12. The member 14 is provided with longitudinally extending V-grooves 15 and 16 (Fig. 3). The V-grooves 15 and 16 serve as supports for rolls of anti-friction balls 17 and 18 respectively. The slide 13 is provided with longitudinally extending members 19 and 20 which are provided with V-grooves 21 and 22 respectively, so as to form an antifriction support for the longitudinally movable slide 13.

The slide 13 is provided with a transversely movable slide 25 which is supported by spaced parallel anti-friction slideways 26 and 27 to facilitate free movement of the slide 25 relative to the longitudinally movable slide 13'. The slideway 26 is provided with an adjustable tapered gib 34 which may be adjusted by a nut and screw mechanism 35 to facilitate taking-up lost motion between the slide 25 and the slideways 2627.

The slide 25 is provided with a vertically arranged cylindrical aperture 28 which contains a cylindrically shaped truing tool carrier 29. A truing tool holder 30 is mounted on the lower end of the carrier 29 and is provided with a truing tool 31 for truing the peripheral face of the grinding wheel 10. The upper end of the carrier 29 is provided with a threaded feed screw 32 which meshes with or engages a nut 33. The nut 33 is held against axial movement relative to the slide 25. A feeding mechanism, to be hereinafter described, is provided for imparting a rotary motion to the feed nut 33 to impart a feeding movement to the truing tool 31 and the carrier 29 relative to the slide 25.

The slide 25 is provided with a follower 40 which is arranged to slide along an operative surface 41 of a forming bar 42. The forming bar is shaped so as to produce a predetermined surface on the operative face of the grinding wheel 10. In case a true cylindrical face is desired on the periphery of the grinding wheel, a forming bar 42 is provided having a plane operative face. If an irregular shape is to be produced, such as, for example, that shown in Fig. l, the face 41 of the forming bar 42 is shaped to correspond with the shape to be produced on the periphery of the grinding wheel 10.

The transversely movable slide 25 is preferably arranged at an angle greater than the angle of repose relative to the path of movement of the longitudinally movable slide 13. The angle of the slide 25 is such that the weight of the slide 25 together with the parts carried thereby serves yieldingly to maintain the follower 40 in operative engagement with the forming bar 42 during the longitudinal movement of the slide 13. The angle of the slide 25 is such that the slide 25 is moved upwardly relative to the longitudinally movable slide 13 due to the resultant thrust of the follower 40 on the surface 41 of the forming bar 42 so that a vertical, angu lar, or curved surface may be generated or trued on the peripheral operative face of the grinding wheel 10.

As illustrated in Figs. 1 and 8, when the slide 13 is moved longitudinally toward the right, the follower 40 rides along a horizontal surface 41a on the forming bar 42 so as to true a cylindrical face 1011 on the grinding wheel. When the follower 40 moves toward the right into engagement with a vertical face 41b on the forming bar 42, continued movement of the slide 13 toward the right produces an upward thrust upon the slide 25 to move it generally in a vertical direction so that the follower 40 follows up the vertical face 41b to true a vertical face 101) on the grinding wheel 10. Continued' movement of the slide 13' toward the right, the follower rides along a horizontal face 410 on the forming. bar 42 to true a cylindrical face 100. The follower 40 then rides down the inclined face 4101 and up the inclined face 4'1e to generate the faces d and We on the operative face of the grinding wheel 10. Continued movement of the slide 13 toward the right traverses the follower 40 across the horizontal face 41f to true a cylindrical face 10 on the grinding wheel 10. Continued movement of the slide 13 toward the right causes the follower 40 to follow the curved face 41g on the forming bar 42 to generate or true the curved face or radius 10g on the grinding wheel 10. Continued movement of the slide 13 toward the right traverses the follower 49' along the horizontal face 4111 to true the cylindrical face 1% on the grinding wheel 10.

The truing apparatus operates in a similar manner during a traversing movement of the slide 13 toward the left. During the movement of the slide toward the left, due to the angular arrangement of the slide 25, the follower 4t) rides along horizontal face 4111 to true the cylindrical face 10h. The follower 4t) rides on the curved face 41g to produce the radius or curved face 10g. The follower 40 then rides along faces 41f, 41c, and 41d successively to true faces 19 141e, and 10d on the grinding wheel 10. The follower 4t} then rides down the vertical face 41b on the forming bar 42 to true vertical face ltlb on the grinding wheel 10. The follower 40 then rides along face 41a to true the cylindrical face 10a on the grinding wheel 10. A variety of shapes have been illustrated on the forming bar 42 to show the applicability of the truing apparatus grinding wheel faces.

In order to facilitate setting up the machine, it is desirable to provide a longitudinal adjusting means for the forming bar 42. As illustrated in Fig. 1, the forming bar 42 is provided with elongated slots 45 and 46'. Clamping screws 47 and 48 pass through the elongated slots 45 and 46 and are screw threaded into a bracket 49 which is preferably adjustably supported on a bracket 50 which is fastened to the upper face of the housing 11. A pair of opposed adjusting screws 51 and 52 are supported by brackets 53 and 54. The brackets 53 and 54 are fixedly mounted on the ends of the brackets 49. If it is desired to adjust the forming bar 42 longitudinally to align the operative face 41 of the forming bar 42 relative to the grinding Wheel 19 to facilitate setting-up the apparatus or to compensate for truing tool wear, the clamping screws 47 and 48 may be loosened after which the screws 51 and 52 may be manipulated to impart a desired longitudinal adjustment tothe forming bar 42. After the forming bar 42 has been located in a desired and predetermined position, the clamping screws 47 and 48 may be again tightened to clamp the forming bar 42 in adjusted position.

The bracket 49 is preferably adjustably supported on the bracket 51 which is fixedly mounted on the wheel guard 11, by means of a pair of clamping screws SS'and 56. The screws 55 and 56 pass through enlarged clearance holes in the bracket 50 and are screw threaded into the bracket 49. If it is desired to impart a vertical adjustment to either or both ends of the forming bar 42, the clamp screws 55 and 56- are loosened after which a pair of adjusting screws 57 and 58 (Fig. 1) may be actuated to raise or lower one or both ends of the forming bar 42 so as to adjust the operative face 41 into a predetermined position. After the forming bar has been precisely located, the clamping screws 55 and 56 may be again tightened so as to clamp the forming bar 42 in an adjusted position.

A hydraulically operated mechanism is provided for imparting a longitudinal traversing movement to the carriage or slide 13. This mechanism comprises a cylinder 60 which is fixedly supported by the housing 12. The cylinder 60 contains a slidably mounted piston 61 which is fixedly mounted on the left hand end of a piston rod 62 (Fig. 8). The right hand end of the piston rod 62 is connected to a bracket 63 which is fixedly mounted on or formed integral with the slide 13. A stop screw 64- carried by the bracket 63 serves to limit the traversing movement of the slide 13 toward the left.

When fluid under pressure is passed through a pipe 65 into a cylinder chamber 66, the piston 61 together with the slide 13 is moved toward the right (Fig. 8). During this movement fluid within a cylinder chamber 67 is exhaused through a pipe 68.

A fluid pressure system is provided for supplying fluid under pressure comprising a motor driven fluid pump '70 which may be started and. stopped by actuation of a switch 71 The pump 7t} draws fluid through a pipe 72 from a reservoir 73 and passes fluid under pressure through a pipe 74 to the various mechanisms of the machine. A. relief valve 75 is connected in the pipe line 74 to facilitate passing. excess fluid under pressuredirectly through a pipe 76 into the reservoir 73 so as to maintain a substantially uniform operating press within the hydraulic system.

A control valve 77 is provided for controlling the admission to and exhaust of fluid from the cylinder 60. The valve 77 is a piston type valve comprising a s-lidably mounted valve member 78 which is provided with a plurality of spaced valve pistons; to form spaced valve chambers 79, 80, and 81. The valve member 78 is provided with a central passage 82 which interconnects the valve chamber 79 with the valve chamber 80-.

The valve member 78 is normally held in a central or neutral postion by a pair of balanced springs 35 and 84. A pair of solenoids S2 and S3 are provided for shifting the valve member 78 in opposite directions. When the solenoid S2 is energized, the valve member 78 is shifted toward the right;

left.

A slow-down valve is provided to throttle the flow of fluid through the pipes 65 and 68-. The valve 90 is a piston type valve having a slidably mounted valve member 91 formed with a plurality of spaced valve pistons to form a pair of spaced valve chambers 92 and 93 therebetween. The valve member 91 is normallyurg'ed in an upward direction by a compression spring;96: to maintain a follower 94 formed on the upper end of thevalve member 91 in operative engagement with a cam 95. The cam 95 is mounted to move with the slide 13 and is arranged so that during'the initial traversing, movement of the slide 13' and the truin'g tool 31, theslide travels at a relatively fast rate of speed controlled by a valve 85. As the 'truing spool 31 approaches engagement with the operative face of the grinding wheel. 10, the follower 94 moves upwardly (Fig. 8) so that the valve chambers 92 and 93 partially cut off the passage of. fluid under pressure and exhaust of fluid under pressure through the pipes 65 and 68 so as to slow downthe traversing movement of the slide 13 so that the truing tool 31 moves at'a desired slow rate of speed across the operative face of the grinding wheel 10.

A suitable feeding mechanism is provided for adjusting the truing tool 31 vertically relative to the slide 25. This mechanism comprises a feed screw 32 fonmedon the upper end of the truing tool holder shaft 29.. A rotatable feed nut 33 meshes with the feed screw 32; A gear 106 is keyed to the feed nut 33 and meshes with a small gear 106 which is keyed on a rotatable shaft 104. The upper end of the shaft 104 is provided with a manual- 13 operable feed wheel 1 07 by means of which the nut When the solenoid 53' is energized, the valve member 7% is shifted toward the 33 may be rotated in either direction vertically to'adjust the position of the truing tool 31.

The grinding wheel truing apparatus is arranged so that either a manual actuation, a manually control in termittent actuation, or a continuous grinding wheel truing cycle may be obtained. A truing tool feeding mechanism is provided which is actuated at the ends of the reciprocatory stroke of the truing tool 31. The down feeding movement of the truing tool 31 may be either a relatively fine or a coarse increment. In order to precisely position the truing tool in its new position, it is desirable to simultaneously impart an unwinding movement to the feed nut 33 and thereafter a winding movement so as to precisely take-up the feed increment and thereby to position the truing tool accurately in its new position for a truing operation.

An oscillatable pate 101 is rotatably supported on a cylindrical hub portion 102 formed on the gear 100. A truing tool unit 103, to be hereinafter described, is fixedly mounted on the underside of the plate 101. The plate 101 is normally held in the position illustrated in Fig, 2 with a stop surface 110 in engagement with a stop abutment 111 (Fig. 2) by means of a compression spring 112.

The truing tool feeding unit 103 is provided with an anti-friction bearing 105 which serves rotatably to support the shaft 104. A ratchet wheel 120 and a worm gear 121 (Fig. 3) are rotatably supported on the shaft.

104 and arranged so that one or the other may be clutched to the shaft 104, as desired. The shaft 104 is arranged for an axial movement relative to the unit 103 so that a clutch drive pin 122 (Fig. 3) fixedly mounted on the shaft .104 may be engaged with a notch formed in the hub of the ratchet wheel 120 to lock the ratchet wheel 120 to the shaft 104. Or the shaft 104 may be moved upwardly so that the drive pin 122 engages a notch formed in the downwardly projecting hub of the worm gear 121.

A spring-pressed detent 123 is arranged to engage one of a plurality of spaced V-grooves formed in the periphery of the shaft 104 so as to hold the shaft 104 so that the clutch pin 122 may be held in a neutral position (Fig. 3), or held in engagement with either the ratchet wheel 120 or the worm gear 121. If the shaft 104 is moved vertically so that the detent engages a central groove in the shaft 104, the drive pin 122 is in a neutral position so that both the ratchet wheel 120 and the worm gear 122 are declutched from the shaft 104. If a very fine feeding increment is desired, the shaft 104 is moved upwardly so that the detent 120 engages the lower groove on the shaft 104 to position the drive pin 122 in an uppermost position so as to lock the worm gear 121 to the shaft 145. If a coarser feeding increment is desired, the shaft 104 is moved downwardly so that the drive pin 122 engages and locks the ratchet Wheel 120 to the shaft 104.

When the slide 13 moves longitudinally toward the right (Fig. 2), the plate 101 engages an adjustable feed dog 114 which serves to rock the plate 101 in a clockwise direction. This movement of the plate 101 serves to move the, now held stationary, gear 106 to impart a clockwise rotary motion to the gear 100, thereby imparting a rotary movement to the feed nut 33 to impart a downward feeding increment to the truing tool 31. As soon as the slide 13 starts moving toward the left, the released compression of the spring 112 rocks the plate 101 in a counterclockwise direction until the stop surface 110 engages the stop abutment 111 thereby imparting a rotary motion to the feed nut 33 to position the tuning tool 31 for a traversing movement toward the left across the operative face of the grinding Wheel 10.

Similarly when the slide 13 approaches the end of its traverse toward the left, the surface 110 on the plate 101 engages the adjustable dog 113 and rocks the plate 101 in a clockwise direction to unwind the feed nut 33. The plate 101 and the nut 33 remain in this position' until the slide 13 starts a traversing movement toward the right for the next truing operation, at which time the released compression of the spring 112 rocks the plate 101 in a counterclockwise direction until the stop surface engages the stop abutment 111 thereby imparting a wind motion to the feed nut 33 so as to position the truing tool 31 for a pass toward the right across the operative face of the grinding wheel 10. It will be readily apparent from the foregoing disclosure that each time the slide 13 approaches either end of its longitudinal traversing movement, the feed nut is backed-01f or unwound. At the start of the traversing movement of the slide 13 in either direction, a feeding increment is im parted to the feed nut 33, and a wind motion is imparted to the feed nut 33 so as to take up the feeding increment precisely to position the truing tool 31 before the truing moves into truing engagement with the opera tive face of the grinding wheel 10.

The unit 103 is provided with a fluid pressure operative mechanism for actuating the ratchet wheel which is arranged so that a down feeding movement of the truing tool 31 may be obtained automatically at the ends of the longitudinal traversing stroke of the truing tool 31 when a truing operation is initiated. This mechanism comprises a cylinder (Fig. 8) which contains a slidably mounted piston 131. The piston 131 is provided with a spring pressed pawl 132 which is arranged to engage the teeth of the ratchet wheel 120. A compression spring 133 serves normally to hold the piston 131 in a downward position.

The piston 131 is provided with an upwardly extending projection 134 which is arranged to engage an adjustable stop screw 135 so as to determine the stroke of the piston 131 and thereby to determine the number of teeth of the ratchet wheel 120 which are picked up during each reciprocation of the piston 131. When fluid under pressure is passed through a pipe 136 into a cylinder chamber 137, the piston 131 is moved upwardly so that the pawl 132 engaging the teeth of the ratchet wheel 120 imparts a clockwise rotary motion to the ratchet wheel 120.

When fluid is exhausted from the cylinder chamber 137 through the pipe 136, the released. compression of the spring 133 causes a downward movement of the piston 131 during which movement the pawl 132 rides idly over the teeth of the ratchet wheel 120. The movement of the piston 131, up and down, is rapid so that the truing tool feed and the wind movement of the feed nut 33 takes place as the truing tool 31 starts its traversing movement toward the right before the truing tool 31 engages the operative face of the grinding wheel 10.

A similar mechanism is provided for imparting a downward feeding movement to the truing tool 31 as it starts a traversing movement toward the left. This mechanism comprises a cylinder 140 which contains a slidably mounted piston 141. The piston 141 is provided with a spring pressed pawl 142 which is arranged to engage the teeth of the ratchet wheel 120. A compression spring 143 serves normally to hold the piston 141 in a downward position. The piston 141 is provided with an upwardly extending projection 144 which is arranged to engage an adjustable stop screw 145. The setting of the stop screw 145 serves to determine the number of teeth of the ratchet wheel 120 picked by the pawl 142 during each reciprocation of the piston 141. When fluid under pressure is passed through a pipe 146 into a cylinder chamber 147, the piston 141 is moved upwardly during which movement the pawl 142 rides idly over the teeth of the ratchet wheel 120. As soon as the slide 13 starts its traversing movement toward the left, fluid within the cylinder chamber 147 is exhausted through the pipe 146 under the influence of the released compression of the spring 143. During the downward movement of the piston 141, the pawl 142 engaging the teeth. of the ratchet wheel 1 20 imparts a clockwise rotary motion to the.

ratchet wheel 120 thereby imparting a predetermined down feed to the truing tool 31. The movement of the piston 141 up and down is rapid so that the truing tool feed and the wind movement of the feed nut 33" takes place as the truing tool 31 starts its traversing movement toward the left before thetruing tool 31- engages the operative face of the grinding wheel 10 If a very fine fe'edi'ngincr'ement is desired, the knob 107 ismoved upwardly to cause an" upward movement of the shaft 104 so that the clutch pin 122 engages and locks the worm gear 121 to the shaft 104. The worm gear 121 meshes with a worm 150 (Fig. 2) which is mounted on a rotatable shaft 151'. The shaft 151 is' provided with apair of spaced ratchet Wheels 152 and 153. The shaft 151 is alsoprovided with a manually operable knob 154 by means of which the mechanism may be actuated manually, if desired.

The pistons 131 and 141 are provided with spring pressed pawls 155 and 156, respectively, which are arranged to ride upon the ratchet wheels 152 and 153, respectively, when the pistons 131 and 141 are moved end-wise ineither direction. The shaft 104 is provided with a serrated wheel or gear 157 (Fig. 8) which is engaged by a spring pressed detent 158 so as to prevent rotary motion of the shaft 104- in a counter-clockwise direct-ion during the idle strokes of the pistons 131- and 141.

A shuttle-type valve 160 is provided for controlling the admission to and exhaust of fluid from the cylinder chambers 137 and 147. The valve 160 is a piston type valve having a slidably mounted valve member 161. The valve member 161 is provided with a plurality of integral spaced valve pistons to form a pair of spaced valve chambers 162 and 163. The valve 160 is provided with. a pair of end chambers 164 and 165 to facilitate rapidly shuttling the valve member 161 in opposite directions- When fluid under pressure is passed through the pipe 65 into the cylinder chamber 66 to start a traversing movement of the piston 61 and the slide 13 toward the right, fluid also passes simultaneously through the valve chamber 162 and the pipe 136 into cylinder chamber 137 to actuate the feed piston 131, and fluid also passes through a pipe 65a into the end chamber 164 rapidly to shift the valve member 161 toward the right.

During the initial movement of the valve member 161 toward the right, fluid under pressure from the pipe 64 passes through the valve chamber 162 and through the pipe 136 into the cylinder chamber 137 to cause an upward movement of the piston 131 thereby actuating the truing tool feeding mechanism. When the valve member 161 approaches the right hand end position, fluid under pressure is cut-ofl from the valve chamber 162 and the valve chamber 162 is. connected so that fluid within the cylinder chamber 137 may exhaust through the valve chamber 162 and the exhaust pipe 76 under the influence of the released compression of the spring 133. piston 131 moves downwardly into a reset position. If the feed mechanism is set for a relatively coarse infeed, the upward movement of the piston imparts a clockwise movement to the ratchet wheel 120 to impart a relatively coarse feeding movement to the truing tool 31. If the mechanism is set for a fine feeding movement, the upward movement of the piston 131, through'thepawl 155 imparts a counter-clockwise movement to the ratchet wheel 152 (Fig. 8) to impart a relatively fine feed to the truing tool 31. Either of these feeding operations takes place during the initial movement of the valve member 161 toward the right. 1

Similarly when the valve member 161 is in a right hand end position, the passage of fluid under pressure through the pipe 68 to start movement of the piston 61 together with the slide 13 toward the left, fluid under pressure also passes through the valve chamber 163, through the pipe 146 into the cylinder chamber 147 so as to-a'ctuate the feed piston 141. Fluid under pressure The 8 passing through the pipe 68' also passes through a; pipe 68a into the end chamber to move the valve member 161 into a left hand end position.

As the valve member 161 reaches a left hand end position, the released compression of the spring 1 43 serves to cause a downward movement of the piston 141. During this movement, fluid within the cylinder chamber 147 exhausts through the pipe 146, through thevalve chamber 163 and through the exhaust pipe 176 into the reservoir 73. During each actuation of the piston 141-, that is, each reciprocation thereof either a fine or a coarse feeding movement is imparted to truing tool 31, depend-- plate 101 so as to impart a rotary unwind movement tothe feed nut 33. When a truing operation is started by energizing either the solenoid S2 or S3, fluid under pressure is passed simultaneously to the cylinder 60 to start a longitudinal movement of the slide 13 and simultaneously to the valve 160 to shift the valve member 161 into a reverse position, and simultaneously to actuate either the piston 131 or the piston 141' so as to impart a rotary feeding movement to the feed nut 33 precisely to advance the truing tool 31 before it traverses intotruing engagement with the operative face of the grinding wheel 10'. As soon as the slide 13 starts a traversing movement in either direction, the plate 101 moves out of engagementwith either the dog 111 or the dog 114 thereby releasing the compression of the spring 112 to impart a counter-clockise rotary motion to the plate 101 thereby imparting a counter-clockwise Wind movement to the feed nut 33 precisely to position the truing tool for the next traversing movement thereof across the operative face of the grinding wheel 10.

The truing tool 31 is fed by a very small increment before each truing operation, consequently it is desirable to impart an unwind and a wind rotary movement to the feed nut before and after each feeding movement to facilitate precisely taking-up the feed increment before the truing tool traverses across the face of the grinding Wheel.

A manually operable means is provided to facilitate raising the slide 25 and the truing tool 31 upwardly to an inoperative position, when desired. This mechanism comprises a manually operable bell crank lever 180- (Figs. 1 and 2) Which is pivotally supported by a stud 181 mounted on the longitudinally movable slide 13. The bell crank lever 180 is provided with a horizontally extending arm 182. The slide 25 is provided with a stud 183 which engages the upper surface of the arm'182. The right hand end of the arm 182 is provided with a notch 184.

When it is desired to raise the slide 25- and the truing tool 31 to an inoperative position, the bell crank lever 180 is rocked in a counter-clockwise direction (Fig. 1') in the broken line position 180a. During this movement the stud 183 rides along the upper surface of the arm 182 to raise the slide 25 into an inoperative broken line position 25. As the slide 25 reaches this position, the stud 183 rides into engagement with notch 184 on the upper end of the arm 182 to latch the slide in an inoperative position.

Similarly, the slide 25 may be moved to an operative position by manually swinging the lever 180 in a clockwise direction from a broken line position 180a into a full line position 18%) thereby allowing the slide 25 together with the truing tool 31 to move downwardly relative to the longitudinally movable slide 13' until the follower 40 moves into operative engagement with the operative face 41 of the forming bar 42.

A modification of the truing apparatus is shown in Fig.

4 for truing an irregularly shaped operative face on the grinding wheel 10. In this disclosure, the longitudinally movable slide 13 is provided with two truing tool units which together serve to true the operative face of the grinding wheel 10. The slide 13 is provided with a pair of angularly arranged transversely movable slides 25a and 25b which are arranged to support truing to'ols 31a and 31b. The construction of each of these truing tool units is identical with that shown in Figs. 1 and 2 and consequently the details thereof will not be described in detail. The truing tool unit on the slide 25a is provided with a feed screw 32a, a gear 109a and a manually operable hand wheel 107a which are connected in a manner identical with that shown in Fig. 3 to facilitate positioning the diamond or truing tool 30a. The truing tool unit carried by the slide 25a is provided with a follower 40a which rides upon the operative face 41 of a forming bar 42a.

The truing tool unit supported by the slide 2511 is provided with a follower 49b which rides upon the operative face of a forming bar 42b. The forming bars 42a and 42b are arranged parallel to each other, one directly in back of the other as shown in Fig. 6. Both of these forming bars are clamped in adjusted position to the bracket 49 (Fig. 6). The truing tool units are each pro vided with independent oscillatable plates 101a and ltllb.

When the slide 13 approaches the left hand end of its stroke, an adjustable dog 113a engages and moves plate 101a in a clockwise direction so as to impart an unwind motion to the feed nut for the truing tool 31a. At the same time, an adjustable dog 1113b engages and moves plate 101]; in a clockwise direction (Fig. 7) so as to impart an unwind motion to the feed nut for the truing tool 31b.

Similarly when the slide 13 approaches the right hand end of its stroke, an adjustable dog 114a engages a stud lltilaa carried by the plate l lla so as to rock the plate 101a in a clockwise direction (Figs. 4 and 7) so as to impart an unwind motion to the feed nut for the truing tool 31a. At the same time, an adjustable dog 11417 engages the plate 101]) and moves the plate 1011) in a clockwise direction (Figs. 4 and 7) so as to impart an unwind motion to the feed nut for the truing tool 31b.

When the slide 13 starts moving in either direction, a feeding movement is imparted simultaneously to advance each of the truing tools 31a and 31b in a manner the same as that described in connection with Figs. 1 and 2. As the slide 13 starts moving either toward the right or toward the left, as the plates 101a or 1011) move away from the dog 113a and 11317 or 114a and 11% respectively, the release compression, a spring, (not shown) which is identical with spring 112 (Figs. 1 and 2) serves to rock the plates 101a and 101b in a counterclockwise direction (Fig. 7) so as to impart a wind motion to each of the feed nuts associated with the feed screws 32a and 32b.

When the slide 13 (Fig. 4) is started traversing to ward the right to true the operative face of the grinding wheel 10, the follower 40b riding upon the face 41m of the forming bar 4212, the truing tool 31b trues the outer peripheral surface x of the grinding wheel 10. The follower 40b rides down the shaped surface 41n of the forming bar 42b and the truing tool 31b trues the portion of the grinding wheel 10 from point 10x to 10y in a manner similar to that described in connection with Figs. 1 and 2.

After the truing tool 311) completes its truing stroke across the face of the grinding wheel 10, the follower 40a riding upon the operative face 411' traverses the truing tool 31a into an engagement with the left hand end side face of the grinding wheel 10, contacting therewith at point 10z. The follower 40a follows an irregular face 41s on the forming bar 42a during which movement the truing tool 31a trues the portion of the grinding wheel face from point Hz to 102:. The slide 13 continues to the right hand end of its stroke with the truing tools moving into positions 31aa and 31bb. The truing apparatus shown in Fig. 4 is precisely adjusted so that the path of the truing tools 31b and 31a are aligned to true the outer peripheral face at 10x. The truing tool 31b trues the outer peripheral surface and truing tool 31a is set and adjusted so that it rides across this outer peripheral surface but does not true any abrading material from the wheel.

The forming bars 42a and 42b are arranged so that they may be adjusted longitudinally to facilitate setting up the truing apparatus and also to facilitate compensation for truing tool wear. A pair of adjusting screws 51a and 52a carried by brackets 53a and 54a serve to facilitate a longitudinal adjustment of the forming bar 42a. Similarly adjusting screws 51b and 52b carried by the brackets 53a and 54a respectively serve to facilitate a longitudinal adjustment of the forming bar 42b. Before making either of these longitudinal adjustments, the clamping screws which hold the forming bars on the bracket 49 are loosened until the desired adjustment has been made. After the forming bars 42a and 42b have been adjusted, as desired, the clamping screws are again clamped to lock the forming bars 42:: and 42b in adjusted position.

By manipulation of these adjusting screws 51a--52a and 51b-52b (Fig. 4) the forming bars 42a and 4212 may be adjusted longitudinally relative to each other so as to facilitate adjusting the path of movement of the truing tools 31a and 31b relative to each and also to facilitate compensation for truing tool wear.

A further modification of the truing apparatus is illustrated in Fig. 5 for truing irregularly shaped surfaces on a grinding wheel 10 having a depressed central portion. In this disclosure the longitudinally movable slide 13 is provided with two truing tool units which together serve to true the operative face of the grinding wheel 10 (Fig. 5). The slide 13 is provided with a pair of angularly arranged transversely movable slides 25c and 25d which are arranged to support truing tools 31c and 31d. It should be noted that, due to the nature of the truing operation, the angular slides 25c and 25d are arranged in a different manner than that shown in Fig. 4. The construction of each of the truing tool units is identical with that shown in Figs. 1 and 2 and consequently the details thereof will not be described in detail.

The truing tool unit on the slide 25c is provided with a feed screw 320, a gear C, and a manually operable hand wheel 1070 which are connected in a manner identical withthat shown in Fig. 3 to facilitate feeding and positioning the truing tool 310. The slide 250 is provided with a follower 40c which rides upon the operative face 41: of the forming bar 420.

The truing tool unit on the slide 25d is provided with a feed screw 32d, a gear 100d, and a manually operable hand wheel 107d which are connected in a manner identical with that shown in Fig. 3 to facilitate feeding and positioning the truing tool 31d. The slide 25d is provided with a follower 40d which rides upon the operative face 411' of a forming bar 42d. The forming bars 420 and 42d are arranged parallel to each other, one directly back of the other, the same as that shown in Fig. 6. Both of these forming bars are adjustably clamped to the bracket 49. The truing tool units are each provided with independent oscillatable plates 101a and 101d respectively which are similar to that shown in Fig. 4. The plate 1010 is provided with a stud 101cc (Fig. 5) which is engaged by a dog 1140 when the slide 13 approaches a right hand end position so as to impart a clockwise motion to the plate ltllc and a corresponding unwind motion to the feed nut.

A pair of adjusting screws 51c and 520 (Fig. 5) are provided to facilitate a longitudinal adjustment of the forming bar 420. A similar pair of adjusting screws 51d and 52d are provided to facilitate a longitudinal adjustment ofthe forming bar 42d; By manipulationofi these adjusting screws, the forming bars 420 and 42d may be adjusted longitudinally relative to each other so as to facilitate adjusting the pathof movement of the truingv tools 31c and 31d relative to each other and to facilitate compensation for truing wear.

The feeding mechanisms of the truing tools 310 and 31d are synchronized so that actuation of the oscillat-able plates 101 and 101d by adjustable dogs 1130 and 1140 or 113d and 114d serves to impart a simultaneous unwind movement to the feed nuts of both of the feed mechanismsfor the truing tools 310 and 31d. This unwinding movement of the feed nut is accomplished as the slide 13' (Fig. approaches either the right hand or the left hand end position. Atthe start of the truing stroke, a feeding movement is imparted tothe feed nut so as to advance the truing tools by a predeterminedincrement' in a manner the same as that disclosed in Figs. 1, 2, and 8. This feeding movement is accomplished when the longitudinally movable slide 13 starts its movement in the reverse direction.

When the slide 13 starts moving either toward the right or toward the left, as the plates 101a or 101d move away from the dogs 1130 or 114b, respectively, the released compression of a spring (not shown) which is identical with the spring 112 (Figs. 1 and 2) serves to rock the plates Mile and 101d in acounterclockwise direction (Fig. 7 so as to impart awind movement to each of the feed nuts associated with the feed screws 32c and 32d respectively.

When a truing operation is initiated and the slide 13 moves toward the right Fig. 5'); the follower 40d riding upon the operative face 411 of the forming bar-42d trues the radius and the peripheral surface adjacent to the point 10m on the grinding wheel 10. The follower 40dthen fcllows surface 41s so that truing tool 3 1d is out of engagement with the grinding wheel until it reaches point ltln (Fig. 5). During continued movement of the slide 13 toward the right, the follower 40d rides up the irregular surface 41x of the forming bar 4262 'to true the portion of the grinding wheel from point 1011' to point 14);). Continued movement of the slide 13 toward the rightv traverses the follower 40d into. position: 4tlda" and the truing tool 30d into position 30dd.

After: the truing tool 31d has completed its pass across the operative face of the wheel 10 to true the portion from point ltln to point Mp, the follower 40c riding upon the surface 411 of the forming bar 420 rides across the peripheral surface adjacent to point 16m and then as the follower 49c rides down irregular surface 415 During thismovement, the truing tool 310 truesthe operative face of the grinding wheel from point 10m to point 1011.

The follower 40 then moves. up: anincline 4'11, across a straight portion and around. a radius to a position 40cc onthe form bar 42c. During this movement, the truing tool. 310 is out of engagement with the grinding wheel until it reaches the portion adjacent lllp where it trues the radius before completing the truing of the grinding wheel face and stopping at aposition 3100.

The truing tool's and 31d are precisely adjusted so that the strokes of the truing tools across the face of the wheel at point ltln overlap each other.

If it is desired to automatically true the grinding wheel after each work piece has been ground, it is. desirable to provide a fine feed to the truing tool. The shaft 104 is moved upwardly so that the clutch pin 122 engages the notch formed in the worm gear 121 so as to provide a fine feeding movement to the truing tool 31' before each traverse of the truing tool across the operative face of the grinding wheel.

A manually operable control lever 170is provided for actuating a start switch 171 when rocked in a counterclockwise direction, and to operate a stop switch" 172 12. whenshifted in a clockwise direction. The start switch 171 is arranged to close acircuit to energizes an electrictimer T1 which may be connected to control the infeeding movement of the grinding wheel so as to control the grinding cycle. This control of the feeding mechanism is old and well known in the prior art and consequently:

has not been illustrated in detail. This arrangement may be substantially identical with that shown in the United States Patent #2572529 to H. S. Silven dated October 23, 1951', to which reference may be had for details of disclosure not contained herein. in this case the timer T1 serves to control the duration. of the grinding cycle, and the truing cycle is initiated when the timer T1 is energized. The truing cycle is completed prior to timing-out of the timer T1.

When the switches SW1 and SW2 are opened, the truing apparatus is arranged for manual control by means of the push button switch PBi. When the switches SW]. and SW2 are closed, actuation of the control lever 170 serves to initiate a grinding cycle and at the same time to initiate a truing cycle so that the truing tool 31 makes a single pass across the operative face of the grinding wheel 10.

When it is desired to start a truing operation, the

I switch 71- is closed to start the fluid pump 7%. The switch SW1 is closed to supply electric power to the circuits as shown in Fig. 8 when an automatic truing cycle is desired before each grinding operation. If a manually operated cycle is desired, the switch SW1 is opened and the switch P31 is manually closed to initiate a truing cycle. When switch FBI is closed, this momentarily completes a circuit through the contacts a of the limit switch LS3 to energize a relay switch R2. Energizing relay switch R2 closes the contacts g and h. The closing of contacts g of the switch R2 sets up a holding circuit to maintain switch R2 energized after the push button switch PE is released. The closing of contacts h of switch R2 serves to complete a circuit to energize the solenoid S2 so as to shift valve member 78 toward the right.

When the valve member 78 moves into a right hand end position fluid under pressure from the valve chamber 80 passes through the pipe 65, through the valve 9 into the cylinder chamber 66- to move the piston 61 together with the slide 13 toward the right. During the initial movement of the slide 13, the piston 61 moves at a relatively fast rate until the follower $4 rides onto the upper surface of the cam thereby releasing the compression of the spring 96 to move the valve member 91 upwardly thereby throttling the flow of fluid through the pipes 65 and 68 to reduce the speed of the truing tool to a predetermined truing speed as it passes across the operative face of the grinding wheel 10.

When the valve member 7 8 is shifted into a right hand end position, fluid passing through the pipe 65 also passes through the pipe 65a to move the valve member 1 61 toward the right. Fluid under pressure passing through the pipe 65 also enters the valve chamber 162 and passes through the pipe 136 to cause an upward movement of the piston 131 so that the pawl 132 imparts a rotary motion through the ratchet wheel to impart a relatively coarse feeding movement to the truing tool 31 if the clutchpin 122 is in a downward position. Or the upward movement of the piston through the pawl imparts a rotary motion to the ratchet wheel 152 if the clutch pin 122 is engaged to lock the worm gear 121 to the shaft 194.

. As the slide 13 moves toward the right, the follower 40 riding along the operative face of the forming bar 42 controls the movement of the truing tool to true a predetermined shape on the peripheral face of the grinding wheel lltl (Fig. 8). The valve member 161 is now in a right hand end position so that the released compression of the spring has caused a downward movement of the piston 131, exhausting fluid from the cylinder chamber as the truing tool 31 moves out of engagement with the grinding Wheel 10.

When the slide 13 reaches the right hand end position of 'ts stroke, the limit switch LS2 is actuated to open the normally closed contacts c thereby breaking the hold circuit to deenergize the relay switch R2. At the same time the normally open contacts d of the limit switch LS2 are closed to close a circuit to make it ready for the next truing operation. The deenergizing of the switch R2 breaks a circuit to deenergize the solenoid S2 thereby allowing the valve member 73 to return to a central position.

the dog 114 (Fig. 2) engages and rocks the plate 101 in a clockwise direction thereby imparting an unwind motion to the feed nut 33.

When it is desired to start the next truing operation, the

switch FBI is manually closed to cause a circuit through the contacts d of the limit switch LS2 to energize the relay switch R3.

As the slide 13 starts its movement toward the left, when the plate 101 moves out of engagement with the dog 114, the released compression of the spring 112 either direction the relay switch R2 and R3 is energized to shift the valve 77 thereby reversing the direction of movement of the slide 13 and causing a movement thereof in the reverse direction.

disclosure. Assuming the parts shown in Fig. 8, the switch 71 is closed to start the fluid motor 70.

the switch FBI is closed which serves to start a longitudinal traversing movement of the slide 13 together with the truing tool 31 toward the right. As soon as the slide 13 starts moving toward the right, the released spring 112 imparts a counterclockwise movement to the plate 101 to impart a wind When it is desired to perform another truing operabutton switch FBI is again actuated to start a traversing movement of the slide 13 together For each actua- 2. A grinding wheel truing apparatus, as claimed in claim 1', in combination with the parts and features therein specified of means actuated by and intimed rela tion with the longitudinal traversing movement of the longitudinally movable slide to imparteither a fine or a coarse feeding increment to said feed mechanism for each truing cycle.

3. In a grinding wheel truing apparatus, as claimed in claim 1-, in combination with the parts and features therein specified in which the longitudinally movable slide is traversed in one direction during each grinding cycle, means to reciprocate said longitudinally movable slide continuously for a continuous truing operation, and means to impart a relatively fine feeding movement to said feed mechanism before each pass of the truing tool across the operative face of the grinding wheel, and means to impart an unwind and a wind motion to the feed nut at each end of the longitudinal movement of said slide.

4'. A grinding wheel truing apparatus, as claimed in claim 1, in which means are provided for adjusting the forming bar longitudinally, and means to clamp said bar in adjusted position.

5. A grinding wheel truing apparatus, as claimed in claim 1, in which a pair of opposed adjusting screws. are provided to facilitate adjusting the forming bar longitudinally so as to adjust the path of movement of the truing tool relative to the grinding wheel and to compensate for truning tool wear.

6. A grinding wheel truing apparatus for truing a predetermined shape on the operative face of a rotatable grinding wheel comprising a base, a longitudinally traversable slide thereon, means to traverse said slide longitudinally in either direction, an angularly arranged transversely movable slide on said longitudinal slide, slid'e Ways interposed between said slides, said trans.- versely movable slide beingv arranged at an angle greater than the angle of repose relative to the longitudinallymovable slide, a vertically arranged truing tool carrier on said transversely movable slide, a truing tool. on said.

carrier, a feeding mechanism interposed between. the transversely movable slide and the carrier, a forming bar on said base having a shape identical with that tobe trued onv the periphery of the grinding wheel, and a follower on said transversely movable slide, said transversely movable slide being arranged to move trans versely relative to the longitudinally movable slide to maintain said follower in operative engagement with the forming bar during itslongitudinal movement so that the resultant thrust of the follower on the forming bar serves to facilitate truing vertical and irregular surfaces on the operative face of the grinding wheel,

7. A grinding wheel truing apparatus for truing a predetermined shape on the operative face of a rotatable grinding wheel comprising a base, a longitudinally traversable slide thereon, means to traverse said slide longitudinally in either direction, a pair of angularly arranged transversely movable slides on said longitudinal movable slide, anti-friction slideways interposed between eachof said slides and the longitudinally movable slide, anindependent vertically arranged truing tool carrier on each of said transversely movable slides, a truing tool on each of said carriers, an independent feed mechanism interposed between each of said transversely movable slides and said carrier, a pair of independently adjustable forming bars on said base, a follower on each of. said transversely movable slides arranged to engage one of said forming, bars, said transversely movable slides being arranged at diverging angles each greater than the angle of repose relative to the longitudinally movable slide so that the followers are maintained in operative engagement with the respective forming bars during longitudinal movement of the longitudinally movable slide, each of saidtruing tools being arranged to true opposite vertical and irregular surfaces on the operative face of the grinding wheel.

8. A grinding wheel truing apparatus, as claimed in claim 7 in which said transversely movable slides are arranged to move transversely relative to the longitudinally movable slide during its longitudinal movement due to the resultant thrusts of the followers on the respective forming bars so as to facilitate truing opposite vertical and irregular surfaces on the operative face of the grinding wheel, said truing tools being arranged to true. overlapping paths on the operative face of the I grinding wheel.

9. A grinding wheel truing apparatus, as claimed in claim 7 in which independent adjusting means are provided independently to adjust said forming bars longitudinally to facilitate adjusting the paths of movementv of the truing tools, and means to clamp the forming bars in adjusted position.

10. A grinding wheel truning apparatus, as claimed in claim 7 of independent feeding mechanisms for feeding each of the truing tools, and means simultaneously to actuate said feeding mechanisms during each truing cycle.

References Cited in the file of this patent UNITED STATES PATENTS 

